<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>javascript 代码块</title>
</head>
<body>
<script>

    function f1() {
        return 123;
    }

    console.log(f1());

    function f2() {
        {
            return 123;
        }
    }

    console.log(f2());

    function f3() {
        {
            {
                {
                    {
                        return 123;
                    }
                }

            }
        }
    }

    console.log(f3());


</script>
</body>
</html>